OpenShift is still missing the client side tools to set environment variables without exposing the values in source code but there is a way to do it. Here is how.
First ssh into your application and navigate to the $OPENSHIFT_DATA_DIR.
Create a file to define your environment.
$ rhc ssh -a difio
Password: ***
[difio-otb.rhcloud.com 51d32a854382ecf7a9000116]\> cd $OPENSHIFT_DATA_DIR
[difio-otb.rhcloud.com data]\> vi myenv.sh
[difio-otb.rhcloud.com data]\> cat myenv.sh
#!/bin/bash
export MYENV="hello"
[difio-otb.rhcloud.com data]\> chmod a+x myenv.sh
[difio-otb.rhcloud.com data]\> exit
Connection to difio-otb.rhcloud.com closed.
Now modify your code and git push to OpenShift. Then ssh into the app once again to verify that your configuration is still in place.
[atodorov@redbull difio]$ rhc ssh -a difio
Password: ***
[difio-otb.rhcloud.com 51d32a854382ecf7a9000116]\> cd $OPENSHIFT_DATA_DIR
[difio-otb.rhcloud.com data]\> ls -l
total 4
-rwxr-xr-x. 1 51d32a854382ecf7a9000116 51d32a854382ecf7a9000116 34 8 jul 14,33 myenv.sh
[difio-otb.rhcloud.com data]\>
Use the defined variables as you wish.
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